In recent years, high sensitization and reduction in the size of silver halide color negative films have progressed so that color negative photographic light-sensitive materials having high sensitivity and providing excellent image quality have been eagerly required.
Many efforts have been made mainly to improve silver halide emulsions for meeting such requirements.
For example, U.S. Pat. Nos. 4,434,226, 4,414,310, 4,433,048, 4,414,306 and 4,459,353 disclose the use of tabular grains with the intention of improving sensitivity by improvement of the efficiency of color sensitization with sensitizing dyes, the relationship between sensitivity and graininess, sharpness, and covering power.
Japanese Patent Application (OPI) Nos. 113930/83 (corresponding to U.S. Pat. No. 4,439,520), 113934/83 (corresponding to U.S. Pat. No. 4,439,520) and 119350/84 (corresponding to European Patent 111,919) (the term "OPI" as used herein refers to a "published unexamined Japanese patent application") disclose multi-layer color photographic light-sensitive materials having high sensitivity and improved graininess, sharpness, and color reproducibility when a tabular silver halide emulsion of 8:1 or more in aspect ratio is used in more sensitive layers.
Further, Japanese Patent Application (OPI) No. 77847/86 discloses a multilayer color photographic light-sensitive material having improved sharpness and color reproducibility when a tabular silver halide emulsion of at least 5:1 in aspect ratio is used in a more sensitive layer and a monodispersed silver halide emulsion is used in a less sensitive layer.
As a result of investigations by the inventors, however, it has been determined that highly sensitive layers, particularly the most sensitive layer of a blue light-sensitive layer does not show satisfactory graininess when a tabular silver halide emulsion is used therein. This may be attributed to the fact that the great sensitization effect by dyes, which is the advantage of tabular grains, is not fully realized in the blue light-sensitive layer.
It is known that, in order to attain excellent photographic properties such as high sensitization, high contrast, and excellent graininess, monodispersed silver halide emulsions having a narrow grain distribution as described in, for example, Japanese Patent Application (OPI) No. 153428/77 (corresponding to U.S. Pat. No. 4,184,878) are advantageous. In addition, it is helpful for the core portion and the shell portion of the grains to both function as emulsion grains from light reception to image formation as much as possible, by using core/shell emulsion grains which contain an internal phase having a different halide composition, to thereby increase the efficiency of using incident light.
Further, it is considered preferable to narrow the distribution of halide composition among grains to obtain highly contrasty emulsions.
However, monodispersed silver halide emulsions of some grain sizes can scatter incident light so much that, particularly when a less sensitive layer contains such a monodispersed emulsion, sharpness is unsatisfactorily reduced due to the scattering of light.